Everyone who is querying and has queried knows that there’s a ton of work and research involved. Fortunately, or unfortunately, there is a lot of great information available at the flick of a screen. Most agencies now have websites where you can read up on each agent and her particular interest. You can also access places like #MSWL, Absolute Write message boards or Query Tracker.
Which is why it’s frustrating when, after a rejection, an author reaches out to ask me who else at BookEnds might be a good fit. If I knew someone else here was perfect for your book I would have forwarded the query. Otherwise, you need to do your own homework. I already have enough of my own.